Add Text To Email Thread - vba

Question

I search my Sent Mail in Outlook and open the last email to a specified email address (this part is done).
I want to add text to the email chain, while keeping the previous messages intact.
The code below creates a "blank-slate" so that all of the previous email correspondence is lost.
What do I need to do to add text to the Body of the email?
FunctionComposeResponse(searchEmail As String, emailBody As String)
Dim currDateTime As Date: currDateTime = Now()
Dim tenDayPrior As Date: tenDayPrior = DateValue(CStr(Now())) - 10 & " 07:00:00 AM"
Dim olApp As Outlook.Application
Dim olNS As NameSpace
Dim Fldr As Folder
Dim olReply As Outlook.MailItem
Dim msg As Object
Set olApp = New Outlook.Application
Set olNS = olApp.GetNamespace("MAPI")
Set Fldr = olNS.GetDefaultFolder(olFolderSentMail)
For Each msg In Fldr.Items
If TypeName(msg) = "MailItem" Then
For Each recipient in msg.recipients
If recip.Address = searchEmail Then
If msg.SentOn >= tenDayPrior And msg.SentOn <= currDateTime Then
Set olReply = msg.ReplyAll
With olReply
.BodyFormat = olFormatHTML
.HTMLBody = emailBody
.Save
.Close olSave
End With
End If
End If
Next recip
End If
Next msg
End Function

Answer 1

By setting
.HTMLBody = emailBody
you overwrite everything that was there before.
You need to insert your text into the existing .HTMLBody.
For new mailitems, where I want to preserve the default HTML signature, I use the following - inspect your existing .HTMLBody to find out if this will also work for Reply (if not: adapt).
' emailBody is plain text -> encode as HTML
emailBody = HtmlEncode(emailBody)
' Outlook-HTML: mail text begins with this line:
' <p class=MsoNormal><o:p> </o:p></p>
' Insert my text instead of the first
oItem.HtmlBody = Replace(oItem.HtmlBody, " ", emailBody, Count:=1)